Chair frame



FIG. 1 is a front perspective view of a chair frame, embodying my new design;

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof; and

FIG. 5 is a top plan view thereof.

The side opposite that which is illustrated in FIG. 2 is a mirror image of FIG. 2. 

The ornamental design for a chair frame, as shown and described. 